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Prediction of degree of localisation of misfit dislocation cores in intercrystalline interfaces based on interfacial adhesion

Witold Łojkowski 

Polish Academy of Sciences, Institute of High Pressure Physics (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland

Abstract

When two crystals form an interface (or grain boundary if they are of the same kind) the local atomic arrangement along the interface is different than in the bulk. There are special orientations of the two crystals and of the interface itself, where the energy of the interface has a minimum as a function of crystallographic parameters characterizing the interface. We will call them LEORs: Low Energy Orientation Relationships. They are also frequently called special interfaces, favoured interfaces, low energy interfaces. In order to minimize energy, interfaces tend to acquire a structure where a large fraction of their area has a structure identical with that of an LEOR. The difference in misorientation angle is taken over by misfit dislocations. However, a challenge is to predict the LEORs as well as the degree of localization of the misfit dislocation cores.
In this paper we show that for that purpose one can use the ratio of the adhesion energy and elastic constants of the crystals. This ratio is expressed numerically as localization parameter p. The system is in a trade of situation, where minimizing misfit leads to decrease local energy in the interface, but increases the long range elastic fields energy. The value of the localization parameter permits to predict which tendency will win: to minimize elastic energy or to minimize misfit energy. It can also predict criteria for low energy interfaces.

 

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Related papers

Presentation: oral at E-MRS Fall Meeting 2005, Symposium F, by Witold Łojkowski
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-30 07:58
Revised:   2009-06-07 00:44